"Too bad we cant just rely on JS only and have to involve a bunch of DOM operations, which is usually the slow part of the UIs we create"

No? With WebGL and soon WebGPU, or in this case here with writing to a imagebuffer and just passing that to canvas, you don't have to use the DOM anymore since quite a while.

(but then you don't get all the nice things html offers, like displaying and styling text etc)

+ built in accessibility + extensions who does something with the DOM + ...

In reality, you're right, there are alternatives, but for the basic web documents, it kind of hurts more than help to use them.